Several sounds edited together into that of a door opening or closing. Sources: http://www.freesound.org/people/swelk/sounds/12906/ http://www.freesound.org/people/swelk/sounds/12907/ http://www.freesound.org/people/Sruddi1/sounds/34880/ http://www.freesound.org/people/ReWired/sounds/48693/ http://www.freesound.org/people/daveincamas/sounds/25709/

This is a sound effect of an airlock created with some freesound samples. http://www.freesound.org/samplesViewSingle.php?id=31474 http://www.freesound.org/samplesViewSingle.php?id=523 http://www.freesound.org/samplesViewSingle.php?id=15983 http://www.freesound.org/samplesViewSingle.php?id=12906

This is a sound effect of an airlock created with some freesound samples. http://www.freesound.org/samplesViewSingle.php?id=31474 http://www.freesound.org/samplesViewSingle.php?id=523 http://www.freesound.org/samplesViewSingle.php?id=15983 http://www.freesound.org/samplesViewSingle.php?id=12906